Mike Gaster ([email protected])

15
Mike Gaster ([email protected]) Boundary layer perturbations created by various boundary value excitations

description

Boundary layer perturbations created by various boundary value excitations. Mike Gaster ([email protected]) ‏. to be imposed on the wall. Velocity perturbations created by a periodic source. Phase locked velocity fluctuations on a smooth plate excited by a periodic point source. - PowerPoint PPT Presentation

Transcript of Mike Gaster ([email protected])

Page 1: Mike Gaster  (m.gaster@qmul.ac.uk)

Mike Gaster ([email protected])

Boundary layer perturbations created by various boundary value excitations

Page 2: Mike Gaster  (m.gaster@qmul.ac.uk)

),(),,( txvtxu to be imposed on the wall

Page 3: Mike Gaster  (m.gaster@qmul.ac.uk)
Page 4: Mike Gaster  (m.gaster@qmul.ac.uk)

Velocity perturbations created by a periodic source

Page 5: Mike Gaster  (m.gaster@qmul.ac.uk)
Page 6: Mike Gaster  (m.gaster@qmul.ac.uk)

Phase locked velocity fluctuations on a smooth plate excited by a periodic point source

C Calculation Measurement

Page 7: Mike Gaster  (m.gaster@qmul.ac.uk)
Page 8: Mike Gaster  (m.gaster@qmul.ac.uk)

Perturbation Created by u(0) = δ(x)

Page 9: Mike Gaster  (m.gaster@qmul.ac.uk)

We can choose appropriate boundary values to model various physical situations:-

jets issuing from a slit or from a point set at an angle to the flow – either steady or unsteady,

an isolated bump, 2-D or 3-D, steady or unsteady,

a periodic roughness ripple, random roughness,

moving roughness.

Transfer function for active control.

Page 10: Mike Gaster  (m.gaster@qmul.ac.uk)

Skin friction from a periodic point source

Re = 1000 Free-stream velocity =12.6m/s

Frequency = 150 Hz

Page 11: Mike Gaster  (m.gaster@qmul.ac.uk)

Fast-nearfield.exeFast-nearfield.exe

Page 12: Mike Gaster  (m.gaster@qmul.ac.uk)

Flow over a sinusoidal ripple

Page 13: Mike Gaster  (m.gaster@qmul.ac.uk)
Page 14: Mike Gaster  (m.gaster@qmul.ac.uk)
Page 15: Mike Gaster  (m.gaster@qmul.ac.uk)

Phase locked velocity fluctuations on a smooth plate excited by a periodic point source

C Calculation Measurement